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For decades, scientists have been baffled by two large, mysterious blobs in Earth’s mantle. These rock formations are thousands of kilometres long and slightly denser than their surroundings, hinting that they are made of different material than the rest of the mantle.
New computer modelling supports a dramatic origin story for these strange blobs: they are artefacts of a gargantuan collision 4.5 billion years ago between early Earth and another young planet — the same collision thought to have formed the Moon1. The modelling suggests that this violent encounter caused material from the impacting world, called Theia, to embed itself in the lower half of Earth’s mantle. The collision also caused some of Theia’s remnants to be flung into orbit; these eventually coalesced into the Moon.
The idea that the mantle anomalies are remnants of Theia is not new, says Robin Canup, a planetary scientist at the Southwest Research Institute in Boulder, Colorado. “But this paper is the first in my mind to really take that notion seriously,” she says.
The study appears today in Nature.
www.nature.com
New computer modelling supports a dramatic origin story for these strange blobs: they are artefacts of a gargantuan collision 4.5 billion years ago between early Earth and another young planet — the same collision thought to have formed the Moon1. The modelling suggests that this violent encounter caused material from the impacting world, called Theia, to embed itself in the lower half of Earth’s mantle. The collision also caused some of Theia’s remnants to be flung into orbit; these eventually coalesced into the Moon.
The idea that the mantle anomalies are remnants of Theia is not new, says Robin Canup, a planetary scientist at the Southwest Research Institute in Boulder, Colorado. “But this paper is the first in my mind to really take that notion seriously,” she says.
The study appears today in Nature.
Strange blobs in Earth’s mantle are relics of a massive collision
Impact with a body called Theia 4.5 billion years ago left remnants deep inside Earth — and also created the Moon.
www.nature.com
